Privacy lock



March 1962 M. E. WILLIAMS 3,025,096

PRIVACY LOCK Filed March 6, 1958 MURRAY E. WILLIAMS Inventor Airy.

3,025,li% Patented Mar. 13, 1962 3,025,096 PRIVACY LOCK Murray E. Williams, Grand Rapids, Mich, assignor to Dexter Industries lne, Grand Rapids, Mich. Filed Mar. 6, 1958, Ser. No. 719,527 4 Claims. (Cl. 292-359) This invention relates to the construction of door locks, and is of a type generally referred to as a privacy set. The purpose of these devices is primarily to serve as a notice that a room is occupied rather than completely exclude all unauthorized entrance. A typical installation of this type of lock is in conjunction with a bathroom door. The primary objective is to prevent someone from blundering in to disturb the privacy of the occupant, and yet make it possible to gain access in case of accident or whenever a child locks himself in without knowledge of how to unlock the device.

The locking system provided by this invention operates in conjunction with a conventional latch mechanism involving a reciprocating bolt. The latch is driven in the usual manner by a square shaft, and the locking action is generated entirely independently of the latch system. As is the usual practice, knob-supporting assemblies are secured in coaxial relationship on opposite sides of the door, one of the components of each of these assemblies being a plate which is normally fixed with respect to the door by conventional mounting screws. According to this invention, a bar is fixed with respect to this plate and is provided with a non-circular opening capable of registering with the square operating shaft to lock the same against rotation. The shaft is provided with a reduced portion, and is axially slideable to and from a position in which the reduced portion is in engagement with the restraining bar. The axial position of the operating shaft therefore determines whether or not the mechanism is in the locked condition. This invention relates to the manner of positioning the shaft so that a locking action is generated which may be cancelled out through the insertion of a suitable key from the outside.

The several details of the invention will be discussed further through an analysis of the particular embodiments illustrated in the accompanying drawings. In the drawmgs:

FIGURE 1 presents an axial section in elevation of a mechanism embodying this invention. The mechanism is illustrated in the unlocked condition.

FIGURE 2 presents a view of a similar axial section as shown in FIGURE 1, but with the device in the locked condition. FIGURE 2 also illustrates the application of a restoring key.

FIGURE 3 presents a perspective view of the inner knob-supporting assembly detached from the door.

Referring to the drawings, the illustrated mechanism may be considered as actuator for a conventional retractor latch bolt mechanism which is not shown. The square operating shaft engages the latch mechanism between the knob-supporting assemblies generally referred to as 11 and 12 in the usual fashion. The shaft 11 provides the necessary torque to operate a rollback system and retractor according to standard practice in this art.

The inner knob-supporting assembly 11 includes a fixed plate 13 which is secured to a door, and has a U- shaped bar 14 secured thereto. As a preferred method of construction, a set of ears 15 and 16 are inserted in suitable openings in the plate 13, and then staked over on assembly. The bar 14 has a central square opening capable of receiving the square cross section of the shaft 10. The shaft is also provided with a reduced portion 17 (preferably circular) which is capable of rotating within the square opening 18 in the bar 14. Axial movement of the shaft 10 would result in placing the reduced portion 17 in and out of engagement with the opening 18 in the bar 14, and therefore determine whether or not the shaft 10 is free to rotate. When in a locked condition, the shaft 10 is moved axially to the right in sufficient amount to again place the square portion of the shaft 10 in engagement with the similarly-shaped opening 18, resulting in the locking of the shaft 11 against rotation regardless of the torque applied by the knob 19.

The outer knob-supporting assembly 12 includes a fixed plate 29 and a tubular member 21 rotatably mounted with respect thereto. The engagement of the washers 22 and 23, maintained by the snap ring 24 maintains the assembled relationship of the components. The washer 23 is provided with a square opening slideably receiving the shaft 10 in driving relationship, and a portion 25 of the tubular member 21 extends through the washer 23 to form a driving connection to transfer torque from the tubular member 21 through the washer 23 to the shaft 10. The knob 1? is keyed in the conventional manner (not shown) to the tubular member 21.

The inner knob-supporting assembly 11 is provided with the tubular member 26 which is rotatably mounted in the fixed plate 13. The controlling button 27 is rotatably and slideably mounted within the tubular member, and has an ear 28 engaging the cam surface 29 formed integrally with the material of the tubular member 26. Rotation of the control button 27 from the position shown in FIGURE 1 to that of FIGURE 2 induces the axial movement involved in the shift from unlocked to locked position. A heavy coil spring 3ft extends the inner end of the control button 27 and the retaining washer 31, which is axially fixed with respect to the square operating shaft 111. A relatively light spring 32 extends from the opposite face of this same retaining washer to the driving washer 33, which is axially fixed with respect to the plate 13. As in the case of the opposite knobsupporting assembly, the tubular member 26 is maintained in fixed axial relationship with the plate 13 by the combined action of the driving washer 33, the washer 34, and the snap ring 35. The projection 36 on the tubular member 26 engages the driving washer 33 for the transfer of torque from the tubular member to the square portion of the shaft 16 through the driving washer 33. Normally, a knob (not shown) slips over the tubular member 26, with the button 27 being accessible through a central opening in the knob.

The axial positioning of the shaft 19 is determined by a balance of the forces between the heavy spring 30 and the light spring 32. Movement to the left of the control button 27 causes the heavier spring 3t) to overpower the lighter spring 32, and move the shaft 10 to the right to where the square portion of the shaft 10 engages the opening 13 in the bar 14, and locks the shaft 10 against rotation. As the control button 27 is restored to the position shown on FIGURE 1, the force against the spring 30 is withdrawn to the left, permitting the light spring 32 to move the shaft 10 back into the position shown in FIG- URE 1 where the reduced portion 17 engages the square opening 18, and permits the shaft to be rotated.

When the unit is in the locked position shown in "FIG- URE 2, it is still possible to open the door in case of an emergency. Insertion of the key 37 through the central non-circular opening 38 in the knob 19 permits the engagement of the inner end of the key with the recess 39 in the end of the operating shaft 11 This engagement serves to locate the end of the key with respect to the shaft 10 so that a pushing action can be applied which is sufficient to compress the spring '30 enough to place the reduced portion 17 in engagement with the opening 18 on the bar 14. Under these conditions, the knob 19 can be rotated to open the door. The non-circular opening 38 permits the key 37 to drive the knob 19 in rotation. The

3 key 37 is preferably kept where it is available for use in such emergencies, but is not normally retained within the opening 38. The escutcheon plate 40 is standard, and forms no part of the invention.

The particular embodiments of the present invention which have been illustrated and discussed herein are for illustrative purposes only and are not to be considered as a limitation upon the scope of the appended claims. In these claims, it is my intent to claim the entire invention disclosed herein, except as I am limited by the prior art.

I claim:

1. A lock mechanism having separable sections installable coaxially on opposite sides of a door, each of said sections including a plate normally fixed with respect to said door and a tubular member rotatably mounted on said plate, one of said tubular members having a manually operable lock control sidably and rotatably mounted therein, the other of said tubular members having a knob non-rotatively engaged therewith, said knob having a central opening in the outer end thereof, said look mechanism comprising: interengaged cam and follower means on said lock control and on the tubular member associated therewith whereby rotary movement of said lock control with respect to said tubular member induces axial movement of said lock control; an operating shaft of non-circular cross-section for cooperation with a latch mechanism, said shaft being unitary and rotatively fixed with respect to said tubular members for rotation therewith and having a portion of reduced cross-section, said shaft also having a recess in the end thereof normally opposite said knob opening, said recess serving to locate with respect to said shaft the end of a member inserted through said knob opening in a direction parallel to said shaft for axially displacing said shaft; a bar normally fixed with respect to said door and having an opening receiving the non-circular portion of said shaft in non-rotative relationship, said reduced portion being rotatable therein; relatively heavy coil spring means extending between a member axially fixed with respect to said shaft and said lock control biasing said shaft towards said knob; and relatively light coil spring means extending between points axially fixed with respect to said shaft and said door, respectively.

2. A lock mechanism according to claim 1 wherein the central opening in said knob is non-circular.

3. A lock mechanism according to claim 1 wherein said relatively heavy coil spring means extends axially between said member and said lock control, and said relatively light coil spring means extends between said member and said point axially fixed with respect to said door.

4. A lock mechanism according to claim 1 wherein said springs bias said shaft axially in opposite directions respectively.

References Cited in the file of this patent UNITED STATES PATENTS 2,497,750 Wardwell Feb. 14, 1950 2,602,318 Belausteguigoitia July 8, 1952 2,640,345 Wardwell June 2, 1953 2,702,466 McConnell Feb. 22, 1955 FOREIGN PATENTS 7,045 Great Britain Apr. 5, 1893 

